A PORTRAIT OF THE TAMPA BAY ESTUARY

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BONNETHEAD SHARK MOBILE

There's a good chance that small fin you see gliding through the seagrass beds of Tampa Bay should only strike terror in the hearts of any crustaceans and small fish that might wander into its path.

That fin is likely to belong to a bonnethead shark (Sphyrna tiburo), which is the smallest in the family of hammerhead sharks, reaching only 3 feet to 4 feet in length. It's one of more than a dozen shark species that populate Tampa Bay.

Like all sharks, the bonnethead is a member of the elasmobranch family, which means it doesn't have a backbone, but instead is made up of strong, lightweight cartilage. Rays and skates also fall into this category.

Unlike some of their larger shark kin, bonnetheads typically remain in inshore waters and are commonly found in bays and estuaries. One of their favorite hangouts is Tampa Bay's seagrass meadows, where they search for small prey like blue crabs, shrimp, mollusks and small fish, and also ingest seagrass itself.

Their sharp front teeth cut up their prey, while the large molars in the back of their mouths grind up harder dinner items.

These sharks are aptly named for the shape of their heads, which resemble a shovel or bonnet. Because their eyes are located at the ends of the rounded lobes of their heads, they have a much greater field of vision.

Their bodies are usually gray or grayish brown, and might have a green tint. They also might have dark spots on their sides.

Like true Floridians, they prefer it when the water temperature is above 70 degrees.

These critters can usually be found swimming in small schools. They're believed to mate during the spring or autumn, and then the females can store sperm for up to four months before actually fertilizing the eggs.

When it's time to give birth, the females move to shallow waters, where they bear between four and 14 live pups. Every pup is about 14 inches long and weighs about 0.4 pounds.

Because bonnetheads frequent inshore waters, it's not uncommon to come across them when you're casting your fishing line.

According to the Florida Museum of Natural History, there's been only one recorded unprovoked bonnethead shark attack on a human, so while other critters in the water may be fleeing, there's no reason for you to do so.